Tsunami risk seems low - seismologist
Paris - The risk of a tsunami being generated by the giant earthquake off Sumatra on Wednesday is low, an expert with the British Geological Survey (BGS) said.
The earthquake's movement was horizontal, not vertical, and caused no apparent movement of the sea floor, which is what triggers tsunamis, seismologist Susanne Sargeant told AFP in Paris by phone.
"We've had two blocks rubbing together, it's called a strike-slip earthquake.
"That means there hasn't been any displacement of the sea floor. Although an earthquake of this magnitude has the potential to cause a large tsunami, the fact that we haven't seen any drop of the sea floor, which is what generates the wave, it looks like the possibility of a tsunami being generated is low."
The US Geological Survey (USGS) said an 8.6-magnitude earthquake struck off the coast of Sumatra at 14:38 (08:38 GMT) at a depth of 33km.
Tsunami alerts or evacuation orders were issued for parts of Malaysia, India, Indonesia, Sri Lanka and Thailand.